Detection of laser beam riding guidance information field is an important method to guarantee the normal operation of the laser beam riding guidance instrument. According to the time and frequency distribution characteristics of laser beam riding guidance signals, the short time Fourier transform (STFT) with the analysis ability of time and frequency characteristics is adopted to analyze the time and frequency characteristics of laser signals simultaneously. Experimental results show that STFT can easily obtain the time and frequency characteristics of laser beam riding guidance signals, which is an efficient detection technology of laser beam riding guidance information field.